Boiler for utilizing fine coal



Sept. 11, 1928..

J. POLLOCK BOILER FOR UTILIZING FINE GOAL Filed Feb. 26, 1927 2 Sheets-Sheet Sept. 11, 1928.

J. POLLOCK BOILER FOR UTILIZING FINE COAL Filed Feb. 26, 1927 2 Sheets-Sheet 2 Patented Sept.v 11, 1928.

UNITED STATES JAMES POLLOGK, OF NEW YORK, N. Y.

BOILER FOR UTILIZING FINE COAL.

Application filed February 26, 1927. Serial No. 171,241.

This invention relates to a steam boiler in which the furnace is adapted for burning chamber is arranged centrally within an outer enclosing wall, an annular steam drum is arranged above the chamber, and an annular container extends downwardl from said drum in the space between the c amber ahd the outer wall. The furnace chamber is open at the top and a hollow header extends over the chamber a short distance from its upperend. This header communicates with the container and with the steam drum. The header and container, filled with water, form baffles which direct the gases from the top of the furnace chamber downwardly along its outer side, and the gases then flow upwardly in the space between the container and the outer wall, and thence pass through fines above the header into the stack. Tubes arranged in a circular series extend downwardly from the header, and tubes in another clrcular series extend downwardl from the steam drum into the path of t e gases flowing around thecontainer, and these tubes are connected to the lower part of the container. The gases in flowing to the stack come in contact with the header and thence flow down- I wardly between the container and the wall of the'furnace chamber, and after passing under the container the gases flow upwardly on its outerside and'thence under the drum to the stack. It is necessary to maintain a balanced pressure over the top of the furnace chamber, in order to prevent the fuel from being drawn out of the chamber before it is consumed. This is controlled by a damper in the stack and by valves in the air pipe, and also by causing the gases which flow over the top of the furnace chamber to take a downward course; The air necessary for combustion of the fuel and for maintaining it in suspension is pro-heated in the stack, and is forced by a pump, in regulated quantity, through the nozzle and also into pockets which are pro.- vided in the furnace wall, and from these pockets, where the air becomes heated to a high temperature, the air flows through passageways into the furnace chamber, at points some distance above the nozzle. This pro-heating of the air gradually increases the efficiency of the furnace.

The arrangement of the furnace and boiler is such as to conserve the heat to the greatest extent.

In the accompanying drawing,

Fig. 1 is a central vertical section through the boiler;

Fig. 2 is a horizontal section on the line 22 of Fig. 1; and,

I Fig. 3 is a partial horizontal section on the line 33 of Fig. 1.

Referring to the drawing, a represents the outer wall of the furnace, which is cylindrical in form, and a indicates the base of the furnace, these parts being made of suitable refractory material and contained within a cagelike structure composed of vertical channel bars 1, the top and bottom plates 2 and 3, the structure as a whole being supportedupon legs or standards, one of which is shown at 1. In the central part of the furnace is arranged a combustion chamber 6 of the type shown in my Patent .No. 1', 530,321; dated March 17, 1925. The

interior wall 5 of this combustion chamber flares upwardly and outwardly, asshown, and in the lower end of the chamber is arranged a nozzle 6, through which fine fuel is blown upwardly by air which is forced into the nozzle throu h a pipe 7. The fuel is fed to the nozzi by mechanism not shown, through a pipe 8.

In the upper part of the furnace an annular steam drum 0 is arranged, this drum fitting closely within the furnace wall, and a stack at fits within the space surrounded by the inner wall of the drum, the drum and stack together extending over the entire space enclosed by the outer wall of the furnace. An annular container e extends downwardl from the drum around the combustion 0 amber to a point near the lower end thereof, and this container is spaced from said chamber in order to provide an annular assagewa-y 9 for ases which flow over t e top of the com ustion chamber. The container is also'spaced from the base a, as shown, to permit the gases to pass under the container. The container is connected at its upper end to the steam drum and at its lower end to a circular series of water tubes 10, arranged between the container and the wall of the combustion chambet, and also to a circular series of water tubes 11, arranged vertically in an annular passageway 12 between the container and the outer wall a of the furnace. As shown, the tubes 10 are connected to the container by Ts 10", and the tubes 11 are connected to the container b Ts 11", and these Ts are in line with short tubes 22, extending horizontally through theflwall of the furnace and provided with caps 22. By removing these caps, a tool may be inserted through the tubes to clean out the connections between the vertical tubes and the container. The upper ends of the tubes 11 are connected to the annular drum 0, as shown, and their lower ends extend through the lower wall of the furnace chamber and are provided with suitable caps 11*. A hollow header f is secured to the inner wall of the container 6 and arranged a short distance above the top of the combustion chamber,

and the series of tubes 10 communicate at suitable intervals, which establish commu nication between the interior of the header and the interior of the annular container.

A pipe 14 leads upwardl from the top wall of the header and has ranches 14 which connect the interior of the header with the interior of the annular drum 0,

A plurality of flues 15 extend throu h the upper part of the container, above t e header 7, and these fines form passageways through which gases may flow from the annular passageway 12 into the stack d. The course of the gases from the combustion chamber to the stack is indicated by the arrows. These gases flow over the top of the combustion chamber, thence downwardly through the annular passageway 9 to the bottom of the container e, thence under the container and upwardly through the passageway 12 to the flues 15, and from thence through the stack.

In the lower part of the outer wall of the furnace is arranged a plurality of horizontal passa eways 16, in which are fitted doors 17 which may be opened to clean out the sediment settling on the bottom wall of the furnace, and sight openings 18 are provided through which the attendant may observe the flame and determine whether the combustion is going on properly in the combustion chamber, or whether a change in the gases and fuel therein.

able to make the combustion more perfect In the stack, which is relatively short, is

arranged a pre-heater g, and at the up e1 end of the stack is arranged an adjusta le damper h, the pre-heater and damper be ing in all respects the same as in my coending application, Serial Number 135,222, hled Sept. 13, 1926. The air for supportin combustion is supplied by a pump is, whic is connected by a pipe 19 to the preeheater g, and from the pre-heater branch pipes 20 lead downwardly to points below the bottom of the furnace, and the ends of these branch pipes extend into arcuate pockets 21 in the wall of the combustion chamber. From these pockets small openings 23 lead through the wall into the combustion chamber, these openings or passageways being preferably tangential to the axis of the combustion chamber, so that the air passing into the combustion chamber will cause a swirl, of

in the pre-heater g and also in the pockets 21, before it enters the furnace. It is found that the pre-heating of the air greatly increases the efficiency of the furnace, and as the wall of the combustion chamber becomes ver hot, the air, in passing throughv the poo ets in the wall of the furnace becomes heated to a high degree.

In 0 eration, the fine coal and coal dust, which 15 fed through the pipe 8, is blown upwardly in the combustion chamber through the nozzle 6, by air which is carried from one of the pipes 20 through pipe 7 to the nozzle. The air pressure is sufi'i cient to maintain the fuel in suspension in the combustion chamber, as explained in my Patent No. 1,530,321. For igniting the fuel, one or more oil burners m are provided in the lower part of the combustion chamber, and after the fuel has become ignited these burners are cut off. The draft through the furnace is controlled so that the pressure in the combustion chamber will not be reduced below atmospheric pressure, as a partial exhaustion of the combustion chamber would interfere with the maintenance of the fuel in" suspension until consumed and would cause some of the unconsumed fuel to pass over the top of the combustion chamber. The gases must flow downwardly from the top of the combustion chamber through the passageway 9, and the damper is arranged so as to retard the flow of gases through the stack so that a balanced pressure is maintained over the combustion chamber, and the fuel, with proper regulation of the air flow, will be maintained in the combustion chamber until it is practically consumed, and nothing but the fine ash will pass over the top of the combustion chamber. The heat is utilized to the fullest extent as the combustion chamber is in the center of the The air is heatedboiler and the flame and gases in passing to the stack are in direct contact with the header 7, tubes 10, annular container 6, tubes 11, and also with the steam drum and with the connections from the header to the drum.

The operator, by looking through the sight holes in the clean-out doors, can determine by the appearance of the flame passing below the annular container whether the combustion is complete, or whether it can be improved by admitting more air, or more fuel, or by regulating the position of the damper to control the draft. The air may be regulated by a suitable hand valve in the air pipe, and the fuel may be regulated by changing the rate of feed. If sediment collects in the bottom ofthe furnace it can be removed through the clean-out doors, and the vertical tubes in the furnace may be cleaned by removing the caps 10* and 11*, on the bottoms of the tubes. Water may be supplied to the furnace through a pipe connection which may be made to the lower end of any one ofthe vertical tubes. The con nections' 10 and 11 between the annular container and the tubes 10 and 11, respectively, may be cleaned by removing the caps from the horizontal tubes 22 which are in line with said connections.

What I claim is:

1. In a steam boiler, a verticallyarranged combustion chamber, open at the top and havingan upwardly flaring inner surface, an outer wall spaced from and surrounding I the combustion chamber and extending above the same, a base connecting said chamber and wall, an annular steam drum, fitting within the upper part of said wall, an annular container connectedto the drum and extending downwardly in the space between" said chamber and wall and spaced from said base, a hollow header, secured to the inner wall of the container and extending over the top of the furnace chamberand spaced therefrom, said headercom'municating with said drum, two circular series of tubes, the tubes of one series extendin downwardly from the header between t e combustion chamber and the container and the tubes of the other seri s extending downwardly from the drum be ween the container and said outer wall, the lower portions of the tubes in each series being connected to the lower end of the container, flues extending through the container above said header, a stack extending across the space surrounded by the drum, a; dam er for regulatin the flow of gases throng the stack, an means for blowing air and fuel, upwardly in said chamber to burn the fuel in suspension therein.

2. In a steam boiler, a vertically arranged combustion chamber, open at the top and having an upwardly flaring inner surface, an outer wall spaced from and surrounding the combustion chamber and extending header, two circular series of tubes, the

tubes of one series extending downwardly from the header between the combustion chamber and the container and the tubes of the other series extending downwardly from the drum between the container and said outer wall, the lower portions of the tubes in each series being connected to the lowerend of the container, flues extending through the container above said header, a stack extending across the space surrounded by the drum, a damper for regulating the flow of gases through the stack, and means for blowing air and fuel upwardly in said chamber to burn the fuel in suspension therein.

3. In a steam boiler, a vertically arranged combustion chamber, open at the top and having an upwardly flaring inner surface, an outer wall spaced from and surrounding the combustion chamber and extending above the same, a base connecting said outer wall and chamber, an annular steam drum fitting within the upper part of said wall, an

annular container connected to the drum and extendin downwardly in the space between said c amber and wall and spaced from said base, a hollow header, secured to the inner wall of the container and extending over the top of the furnace chamber and spaced therefrom, two circular series of tubes, the tubes of one series extending downwardly from the header between the combustion chamber and the container and the tubes of the other series extending downwardly from the drum between the container and said outer wall, the lower portions of the tubes in each series being connected to the lower end of the container and the ends of the tubes extending through said bottom wall and being provided with caps,"flues extending through the container above said header, a stack extending across the space surrounded by the drum, a dam er for re ulating theflow of gases througli the stac and means for blowing air and fuel upwardly in said chamber to burn the fuel in suspension therein. r

4. In a steam boiler, a furnace chamber open at the top and having an upwardly flaring inner surface, an outer wall spaced from the chamber, a base connecting said wall with said chamber, an annular steam drum above the chamber, an annular container extending from the drum downwardly around the chamber and spacer therefrom container and the outer wall, and sight openand also from said base, la header secured ings arranged in said outer wall adjacent to the inner wall of the container and exthe bottom of the container.

tending over the chamber, said header and In testimony whereof I hereunto alfix my 5 container adapted to direct the gases from signature.

said chamber downwardly, thence under the v container, and thence upwardly between the JAMIES POLLOCK. 

